#!/usr/bin/env python
# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai


__license__   = 'GPL v3'
__copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
__docformat__ = 'restructuredtext en'


'''The main GUI'''

import apsw
import errno
import gc
import os
import re
import sys
import textwrap
import time
from collections import OrderedDict, deque
from io import BytesIO
from qt.core import (
    QAction, QApplication, QDialog, QFont, QIcon, QMenu, QSystemTrayIcon, Qt, QTimer,
    QUrl, pyqtSignal
)

from calibre import detect_ncpus, force_unicode, prints
from calibre.constants import (
    DEBUG, __appname__, config_dir, filesystem_encoding, ismacos, iswindows
)
from calibre.customize import PluginInstallationType
from calibre.customize.ui import available_store_plugins, interface_actions
from calibre.db.legacy import LibraryDatabase
from calibre.gui2 import (
    Dispatcher, GetMetadata, config, error_dialog, gprefs, info_dialog,
    max_available_height, open_url, question_dialog, warning_dialog
)
from calibre.gui2.auto_add import AutoAdder
from calibre.gui2.changes import handle_changes
from calibre.gui2.cover_flow import CoverFlowMixin
from calibre.gui2.device import DeviceMixin
from calibre.gui2.dialogs.message_box import JobError
from calibre.gui2.ebook_download import EbookDownloadMixin
from calibre.gui2.email import EmailMixin
from calibre.gui2.init import LayoutMixin, LibraryViewMixin
from calibre.gui2.job_indicator import Pointer
from calibre.gui2.jobs import JobManager, JobsButton, JobsDialog
from calibre.gui2.keyboard import Manager
from calibre.gui2.layout import MainWindowMixin
from calibre.gui2.listener import Listener
from calibre.gui2.main_window import MainWindow
from calibre.gui2.open_with import register_keyboard_shortcuts
from calibre.gui2.proceed import ProceedQuestion
from calibre.gui2.search_box import SavedSearchBoxMixin, SearchBoxMixin
from calibre.gui2.search_restriction_mixin import SearchRestrictionMixin
from calibre.gui2.tag_browser.ui import TagBrowserMixin
from calibre.gui2.update import UpdateMixin
from calibre.gui2.widgets import ProgressIndicator
from calibre.library import current_library_name
from calibre.srv.library_broker import GuiLibraryBroker, db_matches
from calibre.utils.config import dynamic, prefs
from calibre.utils.ipc.pool import Pool
from polyglot.builtins import string_or_bytes, unicode_type
from polyglot.queue import Empty, Queue


def get_gui():
    return getattr(get_gui, 'ans', None)


def add_quick_start_guide(library_view, refresh_cover_browser=None):
    from calibre.ebooks.covers import calibre_cover2
    from calibre.ebooks.metadata.meta import get_metadata
    from calibre.ptempfile import PersistentTemporaryFile
    from calibre.utils.localization import canonicalize_lang, get_lang
    from calibre.utils.zipfile import safe_replace
    l = canonicalize_lang(get_lang()) or 'eng'
    gprefs['quick_start_guide_added'] = True
    imgbuf = BytesIO(calibre_cover2(_('Quick Start Guide'), ''))
    try:
        with lopen(P('quick_start/%s.epub' % l), 'rb') as src:
            buf = BytesIO(src.read())
    except EnvironmentError as err:
        if err.errno != errno.ENOENT:
            raise
        with lopen(P('quick_start/eng.epub'), 'rb') as src:
            buf = BytesIO(src.read())
    safe_replace(buf, 'images/cover.jpg', imgbuf)
    buf.seek(0)
    mi = get_metadata(buf, 'epub')
    with PersistentTemporaryFile('.epub') as tmp:
        tmp.write(buf.getvalue())
    library_view.model().add_books([tmp.name], ['epub'], [mi])
    os.remove(tmp.name)
    library_view.model().books_added(1)
    if refresh_cover_browser is not None:
        refresh_cover_browser()
    if library_view.model().rowCount(None) < 3:
        library_view.resizeColumnsToContents()


class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
        TagBrowserMixin, CoverFlowMixin, LibraryViewMixin, SearchBoxMixin,
        SavedSearchBoxMixin, SearchRestrictionMixin, LayoutMixin, UpdateMixin,
        EbookDownloadMixin
        ):

    'The main GUI'

    proceed_requested = pyqtSignal(object, object)
    book_converted = pyqtSignal(object, object)
    enter_key_pressed_in_book_list = pyqtSignal(object)  # used by action chains plugin
    event_in_db = pyqtSignal(object, object, object)  # (db, event_type, event_data)
    shutting_down = False

    def __init__(self, opts, parent=None, gui_debug=None):
        MainWindow.__init__(self, opts, parent=parent, disable_automatic_gc=True)
        self.setWindowIcon(QApplication.instance().windowIcon())
        self.jobs_pointer = Pointer(self)
        self.proceed_requested.connect(self.do_proceed,
                type=Qt.ConnectionType.QueuedConnection)
        self.proceed_question = ProceedQuestion(self)
        self.job_error_dialog = JobError(self)
        self.keyboard = Manager(self)
        get_gui.ans = self
        self.opts = opts
        self.device_connected = None
        self.gui_debug = gui_debug
        self.iactions = OrderedDict()
        # Actions
        for action in interface_actions():
            if opts.ignore_plugins \
                    and action.installation_type is not PluginInstallationType.BUILTIN:
                continue
            try:
                ac = self.init_iaction(action)
            except:
                # Ignore errors in loading user supplied plugins
                import traceback
                try:
                    traceback.print_exc()
                except Exception:
                    if action.plugin_path:
                        print('Failed to load Interface Action plugin:', action.plugin_path, file=sys.stderr)
                if action.installation_type is PluginInstallationType.BUILTIN:
                    raise
                continue
            ac.plugin_path = action.plugin_path
            ac.interface_action_base_plugin = action
            self.add_iaction(ac)
        self.load_store_plugins()

    def init_iaction(self, action):
        ac = action.load_actual_plugin(self)
        ac.plugin_path = action.plugin_path
        ac.interface_action_base_plugin = action
        ac.installation_type = action.installation_type
        action.actual_iaction_plugin_loaded = True
        return ac

    def add_iaction(self, ac):
        acmap = self.iactions
        if ac.name in acmap:
            if ac.priority >= acmap[ac.name].priority:
                acmap[ac.name] = ac
        else:
            acmap[ac.name] = ac

    def load_store_plugins(self):
        from calibre.gui2.store.loader import Stores
        self.istores = Stores()
        for store in available_store_plugins():
            if self.opts.ignore_plugins \
                    and store.installation_type is not PluginInstallationType.BUILTIN:
                continue
            try:
                st = self.init_istore(store)
                self.add_istore(st)
            except:
                # Ignore errors in loading user supplied plugins
                import traceback
                traceback.print_exc()
                if store.installation_type is PluginInstallationType.BUILTIN:
                    raise
                continue
        self.istores.builtins_loaded()

    def init_istore(self, store):
        st = store.load_actual_plugin(self)
        st.plugin_path = store.plugin_path
        st.installation_type = store.installation_type
        st.base_plugin = store
        store.actual_istore_plugin_loaded = True
        return st

    def add_istore(self, st):
        stmap = self.istores
        if st.name in stmap:
            if st.priority >= stmap[st.name].priority:
                stmap[st.name] = st
        else:
            stmap[st.name] = st

    def add_db_listener(self, callback):
        self.library_broker.start_listening_for_db_events()
        self.event_in_db.connect(callback)

    def remove_db_listener(self, callback):
        self.event_in_db.disconnect(callback)

    def initialize(self, library_path, db, actions, show_gui=True):
        opts = self.opts
        self.preferences_action, self.quit_action = actions
        self.library_path = library_path
        self.library_broker = GuiLibraryBroker(db)
        self.content_server = None
        self.server_change_notification_timer = t = QTimer(self)
        self.server_changes = Queue()
        t.setInterval(1000), t.timeout.connect(self.handle_changes_from_server_debounced), t.setSingleShot(True)
        self._spare_pool = None
        self.must_restart_before_config = False

        for ac in self.iactions.values():
            try:
                ac.do_genesis()
            except Exception:
                # Ignore errors in third party plugins
                import traceback
                traceback.print_exc()
                if getattr(ac, 'installation_type', None) is PluginInstallationType.BUILTIN:
                    raise
        self.donate_action = QAction(QIcon(I('donate.png')),
                _('&Donate to support calibre'), self)
        for st in self.istores.values():
            st.do_genesis()
        MainWindowMixin.init_main_window_mixin(self, db)

        # Jobs Button {{{
        self.job_manager = JobManager()
        self.jobs_dialog = JobsDialog(self, self.job_manager)
        self.jobs_button = JobsButton(parent=self)
        self.jobs_button.initialize(self.jobs_dialog, self.job_manager)
        # }}}

        LayoutMixin.init_layout_mixin(self)
        DeviceMixin.init_device_mixin(self)

        self.progress_indicator = ProgressIndicator(self)
        self.progress_indicator.pos = (0, 20)
        self.verbose = opts.verbose
        self.get_metadata = GetMetadata()
        self.upload_memory = {}
        self.metadata_dialogs = []
        self.default_thumbnail = None
        self.tb_wrapper = textwrap.TextWrapper(width=40)
        self.viewers = deque()
        self.system_tray_icon = None
        do_systray = config['systray_icon'] or opts.start_in_tray
        if do_systray and QSystemTrayIcon.isSystemTrayAvailable():
            self.system_tray_icon = QSystemTrayIcon(self)
            self.system_tray_icon.setIcon(QIcon(I('lt.png', allow_user_override=False)))
            if not (iswindows or ismacos):
                self.system_tray_icon.setIcon(QIcon.fromTheme('calibre-tray', self.system_tray_icon.icon()))
            self.system_tray_icon.setToolTip(self.jobs_button.tray_tooltip())
            self.system_tray_icon.setVisible(True)
            self.jobs_button.tray_tooltip_updated.connect(self.system_tray_icon.setToolTip)
        elif do_systray:
            prints('Failed to create system tray icon, your desktop environment probably'
                   ' does not support the StatusNotifier spec https://www.freedesktop.org/wiki/Specifications/StatusNotifierItem/',
                   file=sys.stderr, flush=True)
        self.system_tray_menu = QMenu(self)
        self.toggle_to_tray_action = self.system_tray_menu.addAction(QIcon(I('page.png')), '')
        self.toggle_to_tray_action.triggered.connect(self.system_tray_icon_activated)
        self.system_tray_menu.addAction(self.donate_action)
        self.eject_action = self.system_tray_menu.addAction(
                QIcon(I('eject.png')), _('&Eject connected device'))
        self.eject_action.setEnabled(False)
        self.addAction(self.quit_action)
        self.system_tray_menu.addAction(self.quit_action)
        self.keyboard.register_shortcut('quit calibre', _('Quit calibre'),
                default_keys=('Ctrl+Q',), action=self.quit_action)
        if self.system_tray_icon is not None:
            self.system_tray_icon.setContextMenu(self.system_tray_menu)
            self.system_tray_icon.activated.connect(self.system_tray_icon_activated)
        self.quit_action.triggered[bool].connect(self.quit)
        self.donate_action.triggered[bool].connect(self.donate)
        self.minimize_action = QAction(_('Minimize the calibre window'), self)
        self.addAction(self.minimize_action)
        self.keyboard.register_shortcut('minimize calibre', self.minimize_action.text(),
                default_keys=(), action=self.minimize_action)
        self.minimize_action.triggered.connect(self.showMinimized)

        self.esc_action = QAction(self)
        self.addAction(self.esc_action)
        self.keyboard.register_shortcut('clear current search',
                _('Clear the current search'), default_keys=('Esc',),
                action=self.esc_action)
        self.esc_action.triggered.connect(self.esc)

        self.shift_esc_action = QAction(self)
        self.addAction(self.shift_esc_action)
        self.keyboard.register_shortcut('focus book list',
                _('Focus the book list'), default_keys=('Shift+Esc',),
                action=self.shift_esc_action)
        self.shift_esc_action.triggered.connect(self.shift_esc)

        self.ctrl_esc_action = QAction(self)
        self.addAction(self.ctrl_esc_action)
        self.keyboard.register_shortcut('clear virtual library',
                _('Clear the Virtual library'), default_keys=('Ctrl+Esc',),
                action=self.ctrl_esc_action)
        self.ctrl_esc_action.triggered.connect(self.ctrl_esc)

        self.alt_esc_action = QAction(self)
        self.addAction(self.alt_esc_action)
        self.keyboard.register_shortcut('clear additional restriction',
                _('Clear the additional restriction'), default_keys=('Alt+Esc',),
                action=self.alt_esc_action)
        self.alt_esc_action.triggered.connect(self.clear_additional_restriction)

        # ###################### Start spare job server ########################
        QTimer.singleShot(1000, self.create_spare_pool)

        # ###################### Location Manager ########################
        self.location_manager.location_selected.connect(self.location_selected)
        self.location_manager.unmount_device.connect(self.device_manager.umount_device)
        self.location_manager.configure_device.connect(self.configure_connected_device)
        self.location_manager.update_device_metadata.connect(self.update_metadata_on_device)
        self.eject_action.triggered.connect(self.device_manager.umount_device)

        # ################### Update notification ###################
        UpdateMixin.init_update_mixin(self, opts)

        # ###################### Search boxes ########################
        SearchRestrictionMixin.init_search_restriction_mixin(self)
        SavedSearchBoxMixin.init_saved_seach_box_mixin(self)

        # ###################### Library view ########################
        LibraryViewMixin.init_library_view_mixin(self, db)
        SearchBoxMixin.init_search_box_mixin(self)  # Requires current_db

        self.library_view.model().count_changed_signal.connect(
                self.iactions['Choose Library'].count_changed)
        if not gprefs.get('quick_start_guide_added', False):
            try:
                add_quick_start_guide(self.library_view)
            except:
                import traceback
                traceback.print_exc()
        for view in ('library', 'memory', 'card_a', 'card_b'):
            v = getattr(self, '%s_view' % view)
            v.selectionModel().selectionChanged.connect(self.update_status_bar)
            v.model().count_changed_signal.connect(self.update_status_bar)

        self.library_view.model().count_changed()
        self.bars_manager.database_changed(self.library_view.model().db)
        self.library_view.model().database_changed.connect(self.bars_manager.database_changed,
                type=Qt.ConnectionType.QueuedConnection)

        # ########################## Tags Browser ##############################
        TagBrowserMixin.init_tag_browser_mixin(self, db)
        self.library_view.model().database_changed.connect(self.populate_tb_manage_menu, type=Qt.ConnectionType.QueuedConnection)

        # ######################## Search Restriction ##########################
        if db.new_api.pref('virtual_lib_on_startup'):
            self.apply_virtual_library(db.new_api.pref('virtual_lib_on_startup'))
        self.rebuild_vl_tabs()

        # ########################## Cover Flow ################################

        CoverFlowMixin.init_cover_flow_mixin(self)

        self._calculated_available_height = min(max_available_height()-15,
                self.height())
        self.resize(self.width(), self._calculated_available_height)

        self.build_context_menus()

        for ac in self.iactions.values():
            try:
                ac.gui_layout_complete()
            except:
                import traceback
                traceback.print_exc()
                if ac.installation_type is PluginInstallationType.BUILTIN:
                    raise

        if config['autolaunch_server']:
            self.start_content_server()

        if show_gui:
            self.show()
        self.read_settings()

        self.finalize_layout()
        self.bars_manager.start_animation()
        self.set_window_title()

        for ac in self.iactions.values():
            try:
                ac.initialization_complete()
            except:
                import traceback
                traceback.print_exc()
                if ac.installation_type is PluginInstallationType.BUILTIN:
                    raise
        self.set_current_library_information(current_library_name(), db.library_id,
                                             db.field_metadata)

        register_keyboard_shortcuts()
        self.keyboard.finalize()
        if self.system_tray_icon is not None and self.system_tray_icon.isVisible() and opts.start_in_tray:
            self.hide_windows()
        self.auto_adder = AutoAdder(gprefs['auto_add_path'], self)

        self.listener = Listener(parent=self)
        self.listener.message_received.connect(self.message_from_another_instance)
        QTimer.singleShot(0, self.listener.start_listening)

        # Collect cycles now
        gc.collect()

        QApplication.instance().shutdown_signal_received.connect(self.quit)
        if show_gui and self.gui_debug is not None:
            QTimer.singleShot(10, self.show_gui_debug_msg)

        self.iactions['Connect Share'].check_smartdevice_menus()
        QTimer.singleShot(1, self.start_smartdevice)
        QTimer.singleShot(100, self.update_toggle_to_tray_action)

        # Once the gui is initialized we can restore the quickview state
        # The same thing will be true for any action-based operation with a
        # layout button. We need to let a book be selected in the book list
        # before initializing quickview, so run it after an event loop tick
        QTimer.singleShot(0, self.start_quickview)

    def start_quickview(self):
        from calibre.gui2.actions.show_quickview import get_quickview_action_plugin
        qv = get_quickview_action_plugin()
        if qv:
            if DEBUG:
                prints('Starting QuickView')
            qv.qv_button.restore_state()
        self.save_layout_state()
        self.focus_library_view()

    def show_gui_debug_msg(self):
        info_dialog(self, _('Debug mode'), '<p>' +
                _('You have started calibre in debug mode. After you '
                    'quit calibre, the debug log will be available in '
                    'the file: %s<p>The '
                    'log will be displayed automatically.')%self.gui_debug, show=True)

    def esc(self, *args):
        self.search.clear()

    def focus_current_view(self):
        view = self.current_view()
        if view is self.library_view:
            self.focus_library_view()
        else:
            view.setFocus(Qt.FocusReason.OtherFocusReason)
    shift_esc = focus_current_view

    def focus_library_view(self):
        self.library_view.alternate_views.current_view.setFocus(Qt.FocusReason.OtherFocusReason)

    def ctrl_esc(self):
        self.apply_virtual_library()
        self.focus_current_view()

    def start_smartdevice(self):
        message = None
        if self.device_manager.get_option('smartdevice', 'autostart'):
            try:
                message = self.device_manager.start_plugin('smartdevice')
            except:
                message = 'start smartdevice unknown exception'
                prints(message)
                import traceback
                traceback.print_exc()
        if message:
            if not self.device_manager.is_running('Wireless Devices'):
                error_dialog(self, _('Problem starting the wireless device'),
                             _('The wireless device driver had problems starting. '
                               'It said "%s"')%message, show=True)
        self.iactions['Connect Share'].set_smartdevice_action_state()

    def start_content_server(self, check_started=True):
        from calibre.srv.embedded import Server
        if not gprefs.get('server3_warning_done', False):
            gprefs.set('server3_warning_done', True)
            if os.path.exists(os.path.join(config_dir, 'server.py')):
                try:
                    os.remove(os.path.join(config_dir, 'server.py'))
                except EnvironmentError:
                    pass
                warning_dialog(self, _('Content server changed!'), _(
                    'calibre 3 comes with a completely re-written Content server.'
                    ' As such any custom configuration you have for the content'
                    ' server no longer applies. You should check and refresh your'
                    ' settings in Preferences->Sharing->Sharing over the net'), show=True)
        self.content_server = Server(self.library_broker, Dispatcher(self.handle_changes_from_server))
        self.content_server.state_callback = Dispatcher(
                self.iactions['Connect Share'].content_server_state_changed)
        if check_started:
            self.content_server.start_failure_callback = \
                Dispatcher(self.content_server_start_failed)
        self.content_server.start()

    def handle_changes_from_server(self, library_path, change_event):
        if DEBUG:
            prints('Received server change event: {} for {}'.format(change_event, library_path))
        if self.library_broker.is_gui_library(library_path):
            self.server_changes.put((library_path, change_event))
            self.server_change_notification_timer.start()

    def handle_changes_from_server_debounced(self):
        if self.shutting_down:
            return
        changes = []
        while True:
            try:
                library_path, change_event = self.server_changes.get_nowait()
            except Empty:
                break
            if self.library_broker.is_gui_library(library_path):
                changes.append(change_event)
        if changes:
            handle_changes(changes, self)

    def content_server_start_failed(self, msg):
        self.content_server = None
        error_dialog(self, _('Failed to start Content server'),
                _('Could not start the Content server. Error:\n\n%s')%msg,
                show=True)

    def resizeEvent(self, ev):
        MainWindow.resizeEvent(self, ev)
        self.search.setMaximumWidth(self.width()-150)

    def create_spare_pool(self, *args):
        if self._spare_pool is None:
            num = min(detect_ncpus(), config['worker_limit']//2)
            self._spare_pool = Pool(max_workers=num, name='GUIPool')

    def spare_pool(self):
        ans, self._spare_pool = self._spare_pool, None
        QTimer.singleShot(1000, self.create_spare_pool)
        return ans

    def do_proceed(self, func, payload):
        if callable(func):
            func(payload)

    def no_op(self, *args):
        pass

    def system_tray_icon_activated(self, r=False):
        if r in (QSystemTrayIcon.ActivationReason.Trigger, QSystemTrayIcon.ActivationReason.MiddleClick, False):
            if self.isVisible():
                if self.isMinimized():
                    self.showNormal()
                else:
                    self.hide_windows()
            else:
                self.show_windows()
                if self.isMinimized():
                    self.showNormal()

    @property
    def is_minimized_to_tray(self):
        return getattr(self, '__systray_minimized', False)

    def ask_a_yes_no_question(self, title, msg, det_msg='',
            show_copy_button=False, ans_when_user_unavailable=True,
            skip_dialog_name=None, skipped_value=True):
        if self.is_minimized_to_tray:
            return ans_when_user_unavailable
        return question_dialog(self, title, msg, det_msg=det_msg,
                show_copy_button=show_copy_button,
                skip_dialog_name=skip_dialog_name,
                skip_dialog_skipped_value=skipped_value)

    def update_toggle_to_tray_action(self, *args):
        if hasattr(self, 'toggle_to_tray_action'):
            self.toggle_to_tray_action.setText(
                _('Hide main window') if self.isVisible() else _('Show main window'))

    def hide_windows(self):
        for window in QApplication.topLevelWidgets():
            if isinstance(window, (MainWindow, QDialog)) and \
                    window.isVisible():
                window.hide()
                setattr(window, '__systray_minimized', True)
        self.update_toggle_to_tray_action()

    def show_windows(self, *args):
        for window in QApplication.topLevelWidgets():
            if getattr(window, '__systray_minimized', False):
                window.show()
                setattr(window, '__systray_minimized', False)
        self.update_toggle_to_tray_action()

    def test_server(self, *args):
        if self.content_server is not None and \
                self.content_server.exception is not None:
            error_dialog(self, _('Failed to start Content server'),
                         unicode_type(self.content_server.exception)).exec_()

    @property
    def current_db(self):
        return self.library_view.model().db

    def refresh_all(self):
        m = self.library_view.model()
        m.db.data.refresh(clear_caches=False, do_search=False)
        self.saved_searches_changed(recount=False)
        m.resort()
        m.research()
        self.tags_view.recount()

    def handle_cli_args(self, args):
        from urllib.parse import unquote, urlparse, parse_qs
        if isinstance(args, string_or_bytes):
            args = [args]
        files, urls = [], []
        for p in args:
            if p.startswith('calibre://'):
                try:
                    purl = urlparse(p)
                    if purl.scheme == 'calibre':
                        action = purl.netloc
                        path = unquote(purl.path)
                        query = parse_qs(unquote(purl.query))
                        urls.append((action, path, query))
                except Exception:
                    prints('Ignoring malformed URL:', p, file=sys.stderr)
                    continue
            elif p.startswith('file://'):
                try:
                    purl = urlparse(p)
                    if purl.scheme == 'file':
                        path = unquote(purl.path)
                        a = os.path.abspath(path)
                        if not os.path.isdir(a) and os.access(a, os.R_OK):
                            files.append(a)
                except Exception:
                    prints('Ignoring malformed URL:', p, file=sys.stderr)
                    continue
            else:
                a = os.path.abspath(p)
                if not os.path.isdir(a) and os.access(a, os.R_OK):
                    files.append(a)
        if files:
            self.iactions['Add Books'].add_filesystem_book(files)
        if urls:
            def doit():
                for action, path, query in urls:
                    self.handle_url_action(action, path, query)
            QTimer.singleShot(10, doit)

    def handle_url_action(self, action, path, query):
        import posixpath

        def decode_library_id(x):
            if x == '_':
                return getattr(self.current_db.new_api, 'server_library_id', None) or '_'
            if x.startswith('_hex_-'):
                return bytes.fromhex(x[6:]).decode('utf-8')
            return x

        if action == 'switch-library':
            library_id = decode_library_id(posixpath.basename(path))
            library_path = self.library_broker.path_for_library_id(library_id)
            if not db_matches(self.current_db, library_id, library_path):
                self.library_moved(library_path)
        elif action == 'show-book':
            parts = tuple(filter(None, path.split('/')))
            if len(parts) != 2:
                return
            library_id, book_id = parts
            library_id = decode_library_id(library_id)
            try:
                book_id = int(book_id)
            except Exception:
                prints('Ignoring invalid book id', book_id, file=sys.stderr)
                return
            library_path = self.library_broker.path_for_library_id(library_id)
            if library_path is None:
                return

            def doit():
                rows = self.library_view.select_rows((book_id,))
                db = self.current_db
                if not rows and (db.data.get_base_restriction_name() or db.data.get_search_restriction_name()):
                    self.apply_virtual_library()
                    self.apply_named_search_restriction()
                    self.library_view.select_rows((book_id,))

            self.perform_url_action(library_id, library_path, doit)
        elif action == 'view-book':
            parts = tuple(filter(None, path.split('/')))
            if len(parts) != 3:
                return
            library_id, book_id, fmt = parts
            library_id = decode_library_id(library_id)
            try:
                book_id = int(book_id)
            except Exception:
                prints('Ignoring invalid book id', book_id, file=sys.stderr)
                return
            library_path = self.library_broker.path_for_library_id(library_id)
            if library_path is None:
                return
            view = self.iactions['View']

            def doit():
                at = query.get('open_at') or None
                if at:
                    at = at[0]
                view.view_format_by_id(book_id, fmt.upper(), open_at=at)

            self.perform_url_action(library_id, library_path, doit)
        elif action == 'search':
            parts = tuple(filter(None, path.split('/')))
            if len(parts) != 1:
                return
            library_id = decode_library_id(parts[0])
            library_path = self.library_broker.path_for_library_id(library_id)
            if library_path is None:
                return
            sq = query.get('eq')
            if sq:
                sq = bytes.fromhex(sq[0]).decode('utf-8')
            else:
                sq = query.get('q')
                if sq:
                    sq = sq[0]
            sq = sq or ''
            vl = None
            if query.get('encoded_virtual_library'):
                vl = bytes.fromhex(query.get('encoded_virtual_library')[0]).decode('utf-8')
            elif query.get('virtual_library'):
                vl = query.get('virtual_library')[0]
            if vl == '-':
                vl = None

            def doit():
                if vl != '_':
                    self.apply_virtual_library(vl)
                self.search.set_search_string(sq)
            self.perform_url_action(library_id, library_path, doit)

    def perform_url_action(self, library_id, library_path, func):
        if not db_matches(self.current_db, library_id, library_path):
            self.library_moved(library_path)
            QTimer.singleShot(0, func)
        else:
            func()

    def message_from_another_instance(self, msg):
        if isinstance(msg, bytes):
            msg = msg.decode('utf-8', 'replace')
        if msg.startswith('launched:'):
            import json
            try:
                argv = json.loads(msg[len('launched:'):])
            except ValueError:
                prints('Failed to decode message from other instance: %r' % msg)
                if DEBUG:
                    error_dialog(self, 'Invalid message',
                                 'Received an invalid message from other calibre instance.'
                                 ' Do you have multiple versions of calibre installed?',
                                 det_msg='Invalid msg: %r' % msg, show=True)
                argv = ()
            if isinstance(argv, (list, tuple)) and len(argv) > 1:
                self.handle_cli_args(argv[1:])
            self.setWindowState(self.windowState() & ~Qt.WindowState.WindowMinimized|Qt.WindowState.WindowActive)
            self.show_windows()
            self.raise_()
            self.activateWindow()
        elif msg.startswith('shutdown:'):
            self.quit(confirm_quit=False)
        elif msg.startswith('bookedited:'):
            parts = msg.split(':')[1:]
            try:
                book_id, fmt, library_id = parts[:3]
                book_id = int(book_id)
                m = self.library_view.model()
                db = m.db.new_api
                if m.db.library_id == library_id and db.has_id(book_id):
                    db.format_metadata(book_id, fmt, allow_cache=False, update_db=True)
                    db.update_last_modified((book_id,))
                    m.refresh_ids((book_id,))
                    db.event_dispatcher(db.EventType.book_edited, book_id, fmt)
            except Exception:
                import traceback
                traceback.print_exc()
        elif msg.startswith('web-store:'):
            import json
            try:
                data = json.loads(msg[len('web-store:'):])
            except ValueError:
                prints('Failed to decode message from other instance: %r' % msg)
            path = data['path']
            if data['tags']:
                before = self.current_db.new_api.all_book_ids()
            self.iactions['Add Books'].add_filesystem_book([path], allow_device=False)
            if data['tags']:
                db = self.current_db.new_api
                after = self.current_db.new_api.all_book_ids()
                for book_id in after - before:
                    tags = list(db.field_for('tags', book_id))
                    tags += list(data['tags'])
                    self.current_db.new_api.set_field('tags', {book_id: tags})
        else:
            prints('Ignoring unknown message from other instance: %r' % msg[:20])

    def current_view(self):
        '''Convenience method that returns the currently visible view '''
        idx = self.stack.currentIndex()
        if idx == 0:
            return self.library_view
        if idx == 1:
            return self.memory_view
        if idx == 2:
            return self.card_a_view
        if idx == 3:
            return self.card_b_view

    def show_library_view(self):
        self.location_manager.library_action.trigger()

    def booklists(self):
        return self.memory_view.model().db, self.card_a_view.model().db, self.card_b_view.model().db

    def library_moved(self, newloc, copy_structure=False, allow_rebuild=False):
        if newloc is None:
            return
        with self.library_broker:
            default_prefs = None
            try:
                olddb = self.library_view.model().db
                if copy_structure:
                    default_prefs = dict(olddb.prefs)
            except:
                olddb = None
            if copy_structure and olddb is not None and default_prefs is not None:
                default_prefs['field_metadata'] = olddb.new_api.field_metadata.all_metadata()
            db = self.library_broker.prepare_for_gui_library_change(newloc)
            if db is None:
                try:
                    db = LibraryDatabase(newloc, default_prefs=default_prefs)
                except apsw.Error:
                    if not allow_rebuild:
                        raise
                    import traceback
                    repair = question_dialog(self, _('Corrupted database'),
                            _('The library database at %s appears to be corrupted. Do '
                            'you want calibre to try and rebuild it automatically? '
                            'The rebuild may not be completely successful.')
                            % force_unicode(newloc, filesystem_encoding),
                            det_msg=traceback.format_exc()
                            )
                    if repair:
                        from calibre.gui2.dialogs.restore_library import (
                            repair_library_at
                        )
                        if repair_library_at(newloc, parent=self):
                            db = LibraryDatabase(newloc, default_prefs=default_prefs)
                        else:
                            return
                    else:
                        return
            self.library_path = newloc
            prefs['library_path'] = self.library_path
            self.book_on_device(None, reset=True)
            db.set_book_on_device_func(self.book_on_device)
            self.library_view.set_database(db)
            self.tags_view.set_database(db, self.alter_tb)
            self.library_view.model().set_book_on_device_func(self.book_on_device)
            self.status_bar.clear_message()
            self.search.clear()
            self.saved_search.clear()
            self.book_details.reset_info()
            # self.library_view.model().count_changed()
            db = self.library_view.model().db
            self.iactions['Choose Library'].count_changed(db.count())
            self.set_window_title()
            self.apply_named_search_restriction('')  # reset restriction to null
            self.saved_searches_changed(recount=False)  # reload the search restrictions combo box
            if db.new_api.pref('virtual_lib_on_startup'):
                self.apply_virtual_library(db.new_api.pref('virtual_lib_on_startup'))
            self.rebuild_vl_tabs()
            for action in self.iactions.values():
                action.library_changed(db)
            self.library_broker.gui_library_changed(db, olddb)
            if self.device_connected:
                self.set_books_in_library(self.booklists(), reset=True)
                self.refresh_ondevice()
                self.memory_view.reset()
                self.card_a_view.reset()
                self.card_b_view.reset()
            self.set_current_library_information(current_library_name(), db.library_id,
                                                db.field_metadata)
            self.library_view.set_current_row(0)
        # Run a garbage collection now so that it does not freeze the
        # interface later
        gc.collect()

    def set_window_title(self):
        db = self.current_db
        restrictions = [x for x in (db.data.get_base_restriction_name(),
                        db.data.get_search_restriction_name()) if x]
        restrictions = ' :: '.join(restrictions)
        font = QFont()
        if restrictions:
            restrictions = ' :: ' + restrictions
            font.setBold(True)
            font.setItalic(True)
        self.virtual_library.setFont(font)
        title = '{0} — || {1}{2} ||'.format(
                __appname__, self.iactions['Choose Library'].library_name(), restrictions)
        self.setWindowTitle(title)

    def location_selected(self, location):
        '''
        Called when a location icon is clicked (e.g. Library)
        '''
        page = 0 if location == 'library' else 1 if location == 'main' else 2 if location == 'carda' else 3
        self.stack.setCurrentIndex(page)
        self.book_details.reset_info()
        for x in ('tb', 'cb'):
            splitter = getattr(self, x+'_splitter')
            splitter.button.setEnabled(location == 'library')
        for action in self.iactions.values():
            action.location_selected(location)
        if location == 'library':
            self.virtual_library_menu.setEnabled(True)
            self.highlight_only_button.setEnabled(True)
            self.vl_tabs.setEnabled(True)
        else:
            self.virtual_library_menu.setEnabled(False)
            self.highlight_only_button.setEnabled(False)
            self.vl_tabs.setEnabled(False)
            # Reset the view in case something changed while it was invisible
            self.current_view().reset()
        self.set_number_of_books_shown()
        self.update_status_bar()

    def job_exception(self, job, dialog_title=_('Conversion error'), retry_func=None):
        if not hasattr(self, '_modeless_dialogs'):
            self._modeless_dialogs = []
        minz = self.is_minimized_to_tray
        if self.isVisible():
            for x in list(self._modeless_dialogs):
                if not x.isVisible():
                    self._modeless_dialogs.remove(x)
        try:
            if 'calibre.ebooks.DRMError' in job.details:
                if not minz:
                    from calibre.gui2.dialogs.drm_error import DRMErrorMessage
                    d = DRMErrorMessage(self, _('Cannot convert') + ' ' +
                        job.description.split(':')[-1].partition('(')[-1][:-1])
                    d.setModal(False)
                    d.show()
                    self._modeless_dialogs.append(d)
                return

            if 'calibre.ebooks.oeb.transforms.split.SplitError' in job.details:
                title = job.description.split(':')[-1].partition('(')[-1][:-1]
                msg = _('<p><b>Failed to convert: %s')%title
                msg += '<p>'+_('''
                Many older e-book reader devices are incapable of displaying
                EPUB files that have internal components over a certain size.
                Therefore, when converting to EPUB, calibre automatically tries
                to split up the EPUB into smaller sized pieces.  For some
                files that are large undifferentiated blocks of text, this
                splitting fails.
                <p>You can <b>work around the problem</b> by either increasing the
                maximum split size under <i>EPUB output</i> in the conversion dialog,
                or by turning on Heuristic processing, also in the conversion
                dialog. Note that if you make the maximum split size too large,
                your e-book reader may have trouble with the EPUB.
                        ''')
                if not minz:
                    d = error_dialog(self, _('Conversion failed'), msg,
                            det_msg=job.details)
                    d.setModal(False)
                    d.show()
                    self._modeless_dialogs.append(d)
                return

            if 'calibre.ebooks.mobi.reader.mobi6.KFXError:' in job.details:
                if not minz:
                    title = job.description.split(':')[-1].partition('(')[-1][:-1]
                    msg = _('<p><b>Failed to convert: %s') % title
                    idx = job.details.index('calibre.ebooks.mobi.reader.mobi6.KFXError:')
                    msg += '<p>' + re.sub(r'(https:\S+)', r'<a href="\1">{}</a>'.format(_('here')),
                                          job.details[idx:].partition(':')[2].strip())
                    d = error_dialog(self, _('Conversion failed'), msg, det_msg=job.details)
                    d.setModal(False)
                    d.show()
                    self._modeless_dialogs.append(d)
                return

            if 'calibre.web.feeds.input.RecipeDisabled' in job.details:
                if not minz:
                    msg = job.details
                    msg = msg[msg.find('calibre.web.feeds.input.RecipeDisabled:'):]
                    msg = msg.partition(':')[-1]
                    d = error_dialog(self, _('Recipe Disabled'),
                        '<p>%s</p>'%msg)
                    d.setModal(False)
                    d.show()
                    self._modeless_dialogs.append(d)
                return

            if 'calibre.ebooks.conversion.ConversionUserFeedBack:' in job.details:
                if not minz:
                    import json
                    payload = job.details.rpartition(
                        'calibre.ebooks.conversion.ConversionUserFeedBack:')[-1]
                    payload = json.loads('{' + payload.partition('{')[-1])
                    d = {'info':info_dialog, 'warn':warning_dialog,
                            'error':error_dialog}.get(payload['level'],
                                    error_dialog)
                    d = d(self, payload['title'],
                            '<p>%s</p>'%payload['msg'],
                            det_msg=payload['det_msg'])
                    d.setModal(False)
                    d.show()
                    self._modeless_dialogs.append(d)
                return
        except:
            pass
        if job.killed:
            return
        try:
            prints(job.details, file=sys.stderr)
        except:
            pass
        if not minz:
            self.job_error_dialog.show_error(dialog_title,
                    _('<b>Failed</b>')+': '+unicode_type(job.description),
                    det_msg=job.details, retry_func=retry_func)

    def read_settings(self):
        geometry = config['main_window_geometry']
        if geometry is not None:
            QApplication.instance().safe_restore_geometry(self, geometry)
        self.read_layout_settings()

    def write_settings(self):
        with gprefs:  # Only write to gprefs once
            config.set('main_window_geometry', self.saveGeometry())
            dynamic.set('sort_history', self.library_view.model().sort_history)
            self.save_layout_state()
            self.stack.tb_widget.save_state()

    def quit(self, checked=True, restart=False, debug_on_restart=False,
            confirm_quit=True):
        if self.shutting_down:
            return
        if confirm_quit and not self.confirm_quit():
            return
        try:
            self.shutdown()
        except:
            import traceback
            traceback.print_exc()
        self.restart_after_quit = restart
        self.debug_on_restart = debug_on_restart
        if self.system_tray_icon is not None and self.restart_after_quit:
            # Needed on windows to prevent multiple systray icons
            self.system_tray_icon.setVisible(False)
        QApplication.instance().quit()

    def donate(self, *args):
        from calibre.utils.localization import localize_website_link
        open_url(QUrl(localize_website_link('https://calibre-ebook.com/donate')))

    def confirm_quit(self):
        if self.job_manager.has_jobs():
            msg = _('There are active jobs. Are you sure you want to quit?')
            if self.job_manager.has_device_jobs():
                msg = '<p>'+__appname__ + \
                      _(''' is communicating with the device!<br>
                      Quitting may cause corruption on the device.<br>
                      Are you sure you want to quit?''')+'</p>'

            if not question_dialog(self, _('Active jobs'), msg):
                return False

        if self.proceed_question.questions:
            msg = _('There are library updates waiting. Are you sure you want to quit?')
            if not question_dialog(self, _('Library updates waiting'), msg):
                return False

        from calibre.db.delete_service import has_jobs
        if has_jobs():
            msg = _('Some deleted books are still being moved to the recycle '
                    'bin, if you quit now, they will be left behind. Are you '
                    'sure you want to quit?')
            if not question_dialog(self, _('Active jobs'), msg):
                return False

        return True

    def shutdown(self, write_settings=True):
        self.shutting_down = True
        self.show_shutdown_message()
        self.server_change_notification_timer.stop()
        try:
            self.event_in_db.disconnect()
        except Exception:
            pass

        from calibre.customize.ui import has_library_closed_plugins
        if has_library_closed_plugins():
            self.show_shutdown_message(
                _('Running database shutdown plugins. This could take a few seconds...'))

        self.grid_view.shutdown()
        db = None
        try:
            db = self.library_view.model().db
            cf = db.clean
        except:
            pass
        else:
            cf()
            # Save the current field_metadata for applications like calibre2opds
            # Goes here, because if cf is valid, db is valid.
            db.new_api.set_pref('field_metadata', db.field_metadata.all_metadata())
            db.commit_dirty_cache()
            db.prefs.write_serialized(prefs['library_path'])
        for action in self.iactions.values():
            action.shutting_down()
        if write_settings:
            self.write_settings()
        if getattr(self, 'update_checker', None):
            self.update_checker.shutdown()
        self.listener.close()
        self.job_manager.server.close()
        self.job_manager.threaded_server.close()
        self.device_manager.keep_going = False
        self.auto_adder.stop()
        # Do not report any errors that happen after the shutdown
        # We cannot restore the original excepthook as that causes PyQt to
        # call abort() on unhandled exceptions
        import traceback

        def eh(t, v, tb):
            try:
                traceback.print_exception(t, v, tb, file=sys.stderr)
            except:
                pass
        sys.excepthook = eh

        mb = self.library_view.model().metadata_backup
        if mb is not None:
            mb.stop()

        self.library_view.model().close()

        try:
            try:
                if self.content_server is not None:
                    # If the Content server has any sockets being closed then
                    # this can take quite a long time (minutes). Tell the user that it is
                    # happening.
                    self.show_shutdown_message(
                        _('Shutting down the Content server. This could take a while...'))
                    s = self.content_server
                    self.content_server = None
                    s.exit()
            except:
                pass
        except KeyboardInterrupt:
            pass
        self.hide_windows()
        if self._spare_pool is not None:
            self._spare_pool.shutdown()
        from calibre.db.delete_service import shutdown
        shutdown()
        time.sleep(2)
        self.istores.join()
        return True

    def run_wizard(self, *args):
        if self.confirm_quit():
            self.run_wizard_b4_shutdown = True
            self.restart_after_quit = True
            try:
                self.shutdown(write_settings=False)
            except:
                pass
            QApplication.instance().quit()

    def closeEvent(self, e):
        if self.shutting_down:
            return
        self.write_settings()
        if self.system_tray_icon is not None and self.system_tray_icon.isVisible():
            if not dynamic['systray_msg'] and not ismacos:
                info_dialog(self, 'calibre', 'calibre '+
                        _('will keep running in the system tray. To close it, '
                        'choose <b>Quit</b> in the context menu of the '
                        'system tray.'), show_copy_button=False).exec_()
                dynamic['systray_msg'] = True
            self.hide_windows()
            e.ignore()
        else:
            if self.confirm_quit():
                try:
                    self.shutdown(write_settings=False)
                except:
                    import traceback
                    traceback.print_exc()
                e.accept()
            else:
                e.ignore()

    # }}}
